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(2009•上海)如果从小明等6名学生中任选1名作为“世博会”志愿者,那么小明被...
(2009•上海)如果从小明等6名学生中任选1名作为“世博会”志愿者,那么小明被选中的概率是 .
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(2003•福州)如图,⊙O的直径AB垂直于弦CD,垂足为H,点P是
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